I notice that when I import invoices via CSV the payment functions are turned off. Is there a way to ensure they are turned on for these invoices?

There's no automatic way to enable payment functions for imported invoices, dNerd. Let me explain further.

When importing invoices via CSV, payment features in QuickBooks default to off because the file mapping doesn’t include the necessary fields to enable this function automatically. You’ll need to enable the payment features manually after importing your invoices.

I'm sharing this article to learn more about importing functionality: Common questions about importing data to QuickBooks Online.

Please comment below if you have further queries, and we're here to help.

@dNerd 

You can check an importer tool as a workaround.

https://get.transactionpro.com/qbo